Remote DBA Experts 11g Features

Oracle 11G New Features

Prepared by: Brian Hays and Jeff Kondas

Much More than Just Great DBA’s

11G New Features

• Flashback data archive• Database replay• SQL performance advisor• SQL plan management• Proactive health checking• Automatic diagnostic repository• Online patching• Patching advisor• Memory management• SQL Cache• SQL Access advisor (Partition)• Virtual columns• Invisible indexes• Transparent tablespace encryption• Create and rebuild indexes online


Flashback Data Archive

• Flashback feature introduced in 9i– Allows viewing of data at a point in time in the

past– System managed undo required– Undo data could be overwritten preventing

flashback operations from occurring

• 10G introduced flashback database– Flash entire database back in time using

flashback recovery logs


Flashback Data Archive

• 11G introduces Flashback Data Archive– Flashback operations now available over an extended

period of time. – Able to specify retention during flashback tablespace

creation. – Use Flashback Data Archive to Generate Reports, for

Trending, to Recover Data, etc. • SELECT product_number, product_name, count FROM

inventory AS OF TIMESTAMP TO_TIMESTAMP ('2007-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS');

– Use log miner GUI to search for specific changes.


Database Replay• Capture all database

activity “like database DVR”.

• Enables user to perform real-world testing– Capture actual database

workload on production system and replay it for testing.

• Test parameter, new release changes– Measure performance impact

using diagnostic tools.


Database Replay

Analyze this!


SQL Performance Analyzer• Compare performance of SQL statements before and after a

system change.• Common Usage Scenarios:

– Upgrade– Parameter Changes – Schema Changes (Indexes)– Optimizer Statistics

• Produce report identifying changes in execution plans or performance of SQL statements. – Measures overall response time of every individual SQL statement

in the workload. – Reveals regressed SQL statements (allowing time to remedy the

problem.)– Offers significant advantage for database tuning.

I KNEW I shouldn’thave reduced the SGA...


SQL Performance Analyzer

Observe how system change will affect each SQL statement in tuning set

Observe overall affect from system change


SQL Plan Management• Preventative tool to track SQL statements

access paths.– Stored in SQL Plan Baseline.– If access path changes, new plan is stored.– Database evaluates performance of new plans and

integrates plans with better performance into SQL Plan Baselines to be accepted or removed.

– Prevents bad access paths from being implemented.

• Provide administrators time to evaluate the access path change.– Interface available to view history of plans.


SQL Plan Management Baselines

Review captured access paths

Analyze each path


Proactive Health Checking

Redo integrity

Undo integrity

Transaction integrity

Dictionary integrity

Validate database

Recovery Advisor

Automatic Monitors


Proactive Health Checking

• “Checkers” results recorded in repository called Automatic Diagnostic Repository.– Redo Integrity Check - scans contents of redo and archive

logs for accessibility and corruption– Undo Segment Integrity Check - finds logical undo corruptions– Transaction Integrity Check - similar to Undo Segment Check

except that it checks only one specific transaction– Dictionary Integrity Check - examines the integrity of core

dictionary objects– DB Structure Integrity Check - verifies integrity of database

files and reports failures if files are inaccessible, corrupt, inconsistent

– Data Block Integrity Check - detects disk image block corruptions


Identify and Resolve Critical Database Issues

• When “checkers” find a problem, information is reported and then fed to recovery advisors.

• New Incident Packaging Service creates a bundle of all issues and supporting files for easy reporting to Oracle Support.

• Reduce time to problem resolution.


Proactive Health Checking Data Recover

Advisor – Auto Recovery Script Generation


Automatic Diagnostic Repository

• Combine incidents into "envelope" – All relevant trace files associated with error are identified

and added to the package and sent to Oracle Support.– Reduce time to problem resolution.


Online Patching

• In Oracle Database 11g, most patches, specifically diagnostic patches, can now be applied online without taking any downtime.

• Reduce planned as well as unplanned downtime.


Patch Advisor

• Setup Metalink credentials in Enterprise Manager and all patches will be automatically downloaded during a patching session.

• Gathers information on available patches based on the features you are using and downloads recommended patches.


Patch Advisor

Determine if there are patches available only for features you are using.

See available CPU patches.


Memory Management• Oracle 9i introduces automatic memory management

– MAX_SGA_SIZE, swaps memory between shared pool and data buffer cache

• Oracle 10g simplifies memory management– SGA_TARGET, allocates specified value for the overall SGA memory

area.

– Memory area PGA is entirely outside the SGA, so is not touched by the

Automatic SGA Management feature • Oracle 11g SGA & PGA one setting

– MEMORY_TARGET, boundary between PGA and SGA are fluid and the memory allowed to flow freely between them

– Avoids wasted memory due to incorrect memory pool settings.


Memory Management

MEMORY_TARGET One setting

Memory Advisor


SQL Access Advisor• SQL Access Advisor has been enhanced

– Helps achieve performance goals by recommending proper set of materialized views, partitions, indexes ,etc.

– Analysis includes considering cost of creation and maintaining access structures.

– Using these structures is essential when optimizing SQL and can result in significant performance improvements.

• Recommendations on improving schema design– Partitioning, indexing, and creating materialized views based

on actual frequency and type of usage.


SQL Access Advisor

Considers cost of creation and maintaining access structures

Advise on complex structures


SQL Result Cache

• Cache in SGA, like buffer cache or PGA

• Accessing memory is far quicker than accessing hard drives – When queries and functions are executed repeatedly, results

are retrieved directly from cache memory– Results in faster response time

• Execute with hint result_cache– Stores results of SQL queries and PL/SQL functions in area

called Result Cache Memory– Allows lookup, rather than recalculation.– A change in the underlying table invalidates the cache,

resulting in dynamic refresh next time it is queried.


Virtual Columns• Enable application developers to define computations and

transformations as column definition of tables without space consumption

• Offers the flexibility to add columns that convey business sense without adding any complexity to code or performance impact. SQL> create table sales 2 (3 sales_id number, 4 cust_id number, 5 sales_amt number, 6 sale_category varchar2(6) 7 generated always as 8 ( 9 case 10 when sales_amt <= 10000 then 'LOW' 11 when sales_amt > 10000 and sales_amt <= 100000 then 'MEDIUM' 12 when sales_amt > 100000 and sales_amt <= 1000000 then 'HIGH' 13 else 'ULTRA' 14 end 15 ) virtual


Invisible Indexes

• Is this index really beneficial?– Oracle 11g offers option to make indexes invisible to optimizer.– alter index employee invisible;

• Analyze impact index is having on system without affecting performance.– Great for testing.


Transparent Tablespace Encryption

• Transparent Data Encryption (10g R2)– Performance is an issue with this feature.

Index range scan cannot be applied to encrypted columns.

• Transparent Tablespace Encryption (11g)– All data in the tablespace is encrypted.– Index scanning occurs in memory where the data is

unencrypted, causing no performance impact.


Create and Rebuild Index Online

• The online clause rebuilds the index without affecting the DML. – In 10g the operation required an exclusive lock at the end

of the process and DMLs had to wait. Caused concurrency waits.

• In Oracle Database 11g, the online rebuild is truly online, does not hold exclusive lock and DMLs are not affected.– Maintain indexes without affecting system performance.


References

• The Top New Features for DBAs and Developers ; Arup Nanda ; Oracle Press

• www.oracle.com, technet.oracle.com

• All companies and product names are trademarks or

registered trademarks of the respective owners.

• All Oracle11g Documentation

http://www.oracle.com/

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Remote DBA Experts 11g Features

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